Add annotations to Type and Kind - #3484

If the tests are passing we should probably get this in asap and work out how to make the errors better afterwards - any time I've attempted this in the past, the slightest drift in master makes keeping these kind of branches up to date agonising.

The only concern I have is around bloat of various JSON things. CoreFn doesn't emit types right now, I don't think, so it's not a problem there, but the stuff around docs/publish do. Is this something to be concerned about? Or even just leaking things like path names.

Also, I kept the Eq and Ord instances, but they just ignore annotations. Removing the instances broke lots of other derived instances. While omitting them in Eq/Ord is a little dubious, it should at least be identical to the previous behavior.

I've updated the Docs code to use () as the annotation, so it shouldn't leak source spans.

Will this affect the externs format?

Not appreciably, but it will keep annotations on types and kinds. Do you have any specific concerns?

Re specific concerns on the externs format: not really. We don't consider the externs format part of the public interface, right? It's only meant to be for the use of the compiler? I was just wondering because pulp makes use of https://github.com/hdgarrood/purescript-externs-check, which will check whether your main looks like its type makes sense for use as an entry point.

It's possible that it could affect that yes, because the codec for Type is automatically derived. For Kind, I made a point to add the annotation as an extra field, and not part of contents, which preserves compatibility.

Ok, great. Just to clarify I don't think the externs format issue should affect the mergeability of this PR, it's just handy to know about in advance from the point of view of pulp.

I think I've addressed your comments.

I created #3494 to track the specific issue with Type.

🎉